The present invention relates to a unit for supporting a plurality of sprockets on a fluted cylindrical body associated with a hub of a bicycle rear wheel, of the type comprising at least one intermediate supporting member mounted on said cylindrical body by means of a fluted coupling and carrying on its turn at least one sprocket attached thereto by means of connecting elements.
A supporting unit of the above indicated type is disclosed for example in European Patent EP-B-0 510 371 and in the corresponding U.S. Pat. No. 5,194,051.
In this known solution, the above mentioned intermediate supporting body is constituted by a body of light alloy including a bush mounted by means of a fluted coupling on the aforesaid cylindrical body associated with the hub of the bicycle (this cylindrical body being typically the body of the free wheel associated with the hub) as a plurality of arms extending radially outwardly from the periphery of the aforesaid bush and inclined so as to lie on a common conical surface, these arms having stepped front surfaces having holes for engagement of screws for securing the sprockets.
Solutions of the above indicated type have been proposed in the endeavour to decrease the weight of the sprocket unit while rendering the operations for mounting the sprockets easier. However, solutions of this type have the drawback of being relatively complicated and expensive to manufacture.